In situ high-temperature X-ray diffraction characterization of silver sulfide, Ag2S

2011 ◽  
Vol 26 (2) ◽  
pp. 114-118 ◽  
Author(s):  
Thomas Blanton ◽  
Scott Misture ◽  
Narasimharao Dontula ◽  
Swavek Zdzieszynski
Keyword(s):  
High Temperature ◽  
Structure Refinement ◽  
Silver Sulfide ◽  
Rietveld Analysis ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Fcc Phase

Silver sulfide, Ag2S, is most commonly known as the tarnish that forms on silver surfaces due to the exposure of silver to hydrogen sulfide. The mineral acanthite is a monoclinic crystalline form of Ag2S that is stable to 176°C. Upon heating above 176°C, there is a phase conversion to a body-centered cubic (bcc) form referred to as argentite. Further heating above 586°C results in conversion of the bcc phase to a face-centered cubic (fcc) phase polymorph. Both high-temperature cubic phases are solid-state silver ion conductors. In situ high-temperature X-ray diffraction was used to better understand the polymorphs of Ag2S on heating. The existing powder diffraction file (PDF) entries for the high-temperature fcc polymorph are of questionable reliability, prompting a full Rietveld structure refinement of the bcc and fcc polymorphs. Rietveld analysis was useful to show that the silver atoms are largely disordered and can only be described by unreasonably large isotropic displacement parameters or split site models.

Grain Growth and Mechanical Properties of Nanograined Bulk Fe-25Ni Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 3459-3462
Author(s):  
Hong Bin Wang ◽  
Xiao Yu Wang ◽  
J.H. Zhang ◽  
T.Y. Hsu
Keyword(s):  
Mechanical Properties ◽  
Grain Growth ◽  
Coarse Grained ◽  
Growth Exponent ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Ni Alloy ◽  
Face Centered ◽  
Fcc Phase

The grain growth and mechanical properties of nanograined bulk Fe-25at%Ni alloy prepared by an inert gas condensation and in-situ warm consolidation technique were investigated. About 43% high temperature face-centered-cubic (FCC) phase and 57% low temperature body-centered-cubic (BCC) phase were observed in the sample at room temperature, which was significantly different from that of the corresponding conventional coarse-grained alloy. The in-situ X-ray diffraction results show that the start and the finish temperature of BCC to FCC phase transformation are 450°C and 600°C, respectively. The isothermal grain growth exponent n from t k D D n n ¢ = − 1 0 1 for nanograined single FCC phase Fe-25at%Ni alloy is 0.38 at 750 °C . The mechanical properties changing with the grain size were studied by means of microindentation test.

High-temperature X-ray diffraction and thermal expansion of nanocrystalline and coarse-crystalline acanthite α-Ag2S and argentite β-Ag2S

2016 ◽  
Vol 18 (6) ◽  
pp. 4617-4626 ◽  
Author(s):  
S. I. Sadovnikov ◽  
A. I. Gusev ◽  
A. V. Chukin ◽  
A. A. Rempel
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Diffraction Method ◽  
Silver Sulfide ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

An in situ study of thermal expansion of polymorphic phases of coarse-crystalline and nanocrystalline silver sulfide – monoclinic acanthite α-Ag2S and cubic argentite β-Ag2S – has been carried out for the first time using the high-temperature X-ray diffraction method.

Hydrogen-induced structural transformation of AuCu nanoalloys probed by synchrotron X-ray diffraction techniques

Nanoscale ◽  
2014 ◽  
Vol 6 (8) ◽  
pp. 4067-4071 ◽  
Author(s):  
M. Yamauchi ◽  
K. Okubo ◽  
T. Tsukuda ◽  
K. Kato ◽  
M. Takata ◽  
...  
Keyword(s):  
Structural Transformation ◽  
Hydrogen Atmosphere ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered

In situ X-ray diffraction measurements reveal that the transformation of a AuCu nanoalloy from a face-centered-cubic to an L10 structure is accelerated under a hydrogen atmosphere.

In Situ X-Ray Diffraction Analysis of Face-Centered Cubic Metals Deformed at Room and Cryogenic Temperatures

2019 ◽  
Vol 28 (8) ◽  
pp. 4658-4666
Author(s):  
Marcel Tadashi Izumi ◽  
John Jairo Hoyos Quintero ◽  
Maicon Rogerio Crivoi ◽  
Milene Yumi Maeda ◽  
Ricardo Sanson Namur ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Face Centered Cubic ◽  
Cryogenic Temperatures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Metals ◽  
Face Centered

New designs of hydrophobic and mesostructured Ultra Low k materials with isolated mesopores

2011 ◽  
Vol 1335 ◽  
Author(s):  
Anthony Grunenwald ◽  
André Ayral ◽  
Pierre Antoine Albouy ◽  
Vincent Rouessac ◽  
David Jauffres ◽  
...  
Keyword(s):  
Grazing Incidence ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
X Ray Scattering ◽  
Face Centered ◽  
Film Porosity ◽  
Low K

ABSTRACTIn this work, hydrophobic mesostructured organosilica thin films, exhibiting isolated mesopores (~ 7 nm), have been successfully deposited by spin-coating using different polystyrene-block-polyethylene oxide copolymers (PS-b-PEO) as structure-directing agents and methyltriethoxysilane (MTES) as organosilica precursor. Different ordered mesostructures (Face Centered Cubic, 2D or 3D Hexagonal and Body Centered Cubic) can be achieved by controlling different synthesis parameters. X-Ray Diffraction (XRD) and Grazing Incidence Small Angle X-Ray Scattering (GISAXS) techniques were used to investigate the mesostructure evolution through thermal and UV treatments. Swelling and shrinkage were evidenced by in-situ XRD and X-Ray Reflectivity measurements during the thermal removal of the meso-templates. Infrared spectroscopy and 29Si NMR were additionally used to investigate the microstructure evolution. The film porosity was estimated thanks to Ellipsometry Porosimetry (EP). Correlation between mechanical properties through nanoindentation measurements and the mesostructure ordering is discussed as well as assessments of the dielectric constant k by mercury contact probe.

Metallurgical Aspects of High-palladium Alloys

1988 ◽  
Vol 67 (10) ◽  
pp. 1307-1311 ◽  
Author(s):  
P.R. Mezger ◽  
A.L.H. Stols ◽  
M.M.A. Vrijhoef ◽  
E.H. Greener
Keyword(s):  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Palladium Alloys ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Simple Cubic ◽  
Face Centered ◽  
Fcc Phase ◽  
Multi Phase

Nine commercial high-Pd alloys were investigated. Microstructure and phase composition were screened by x-ray diffraction, light microscopy, and an electron microprobe. After being etched, some high-Pd alloys revealed dendritic structures. The others showed a more homogeneous structure with distinct grain boundaries. Etching was necessary to reveal distinct structures, though the overall etching effect turned out to be limited. On unetched specimens, only a slight chemical heterogeneity could be determined. Except for one alloy, the systems turned out to have complex multi-phase structures. The main face-centered-cubic (fcc) phase was Pd-based. As secondary phases, body-centered-cubic (bcc) and/or simple cubic ones were detected. The latter phases were similar to a Cu3Ga and PdGa intermetallic compound, respectively. Face-centered-tetragonal (fct) structures reported by other investigators were not found.

Crystallization kinetics of atomic crystals revealed by a single-shot and single-particle X-ray diffraction experiment

2021 ◽  
Vol 118 (51) ◽  
pp. e2111747118
Author(s):  
Akinobu Niozu ◽  
Yoshiaki Kumagai ◽  
Toshiyuki Nishiyama Hiraki ◽  
Hironobu Fukuzawa ◽  
Koji Motomura ◽  
...  
Keyword(s):  
Materials Science ◽  
Natural Phenomenon ◽  
Stable Phase ◽  
Single Shot ◽  
Face Centered Cubic ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Fcc Phase

Crystallization is a fundamental natural phenomenon and the ubiquitous physical process in materials science for the design of new materials. So far, experimental observations of the structural dynamics in crystallization have been mostly restricted to slow dynamics. We present here an exclusive way to explore the dynamics of crystallization in highly controlled conditions (i.e., in the absence of impurities acting as seeds of the crystallites) as it occurs in vacuum. We have measured the early formation stage of solid Xe nanoparticles nucleated in an expanding supercooled Xe jet by means of an X-ray diffraction experiment with 10-fs X-ray free-electron laser (XFEL) pulses. We found that the structure of Xe nanoparticles is not pure face-centered cubic (fcc), the expected stable phase, but a mixture of fcc and randomly stacked hexagonal close-packed (rhcp) structures. Furthermore, we identified the instantaneous coexistence of the comparably sized fcc and rhcp domains in single Xe nanoparticles. The observations are explained by the scenario of structural aging, in which the nanoparticles initially crystallize in the highly stacking-disordered rhcp phase and the structure later forms the stable fcc phase. The results are reminiscent of analogous observations in hard-sphere systems, indicating the universal role of the stacking-disordered phase in nucleation.

Stabilization of Thick Fcc Cobalt Layers by One Monolayer of Manganese in Co/Mn Superlattices

1998 ◽  
Vol 528 ◽  
Author(s):  
V. Pierron-Bohnes ◽  
A. Michel ◽  
J.P. Jay ◽  
P. Panissod
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Buffer Layer ◽  
Structural Properties ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Face ◽  
Face Centered ◽  
Fcc Phase

AbstractEpitaxial Co/Mn superlattices (0.6 to 4.8 nm thick Co) have been grown on (0002) hcp Ru buffer layer on mica substrates. The face centered cubic (fcc) phase of cobalt is stabilized by the very thin manganese layer. The structural properties of these layers have been studied through x ray diffraction and nuclear magnetic resonance.

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